AT&T has announced plans to upgrade its nationwide 3G network in the U.S. to deliver considerably faster mobile broadband speeds. The network upgrades are slated to begin later this year, with completion expected in 2011.

The upgrade will bring High Speed Packet Access (HSPA) 7.2 technology to service. The company has built its network on the 3G UMTS technology that is commonly deployed throughout the world.

AT&T plans to boost the speed of its mobile broadband network and offer a wide variety of devices to take advantage of it well in advance of 2011-2012, when most industry observers expect 4G LTE networks and device availability to scale.

Currently AT&T plans to begin LTE trials in 2010, with deployment beginning in 2011.

In addition to the planned speed upgrade, AT&T is enhancing its mobile broadband coverage by nearly doubling the wireless spectrum dedicated to 3G in most metropolitan areas to deliver stronger in-building reception and more overall network capacity. Also, AT&T is adding thousands of new cell site backhaul connections to support the higher mobile broadband speeds enabled by HSPA 7.2 and LTE.

“AT&T’s network infrastructure gives us a tremendous advantage in that we’re able to deliver upgrades in mobile broadband speed and performance with our existing technology platform,” said Ralph de la Vega, president and CEO, AT&T Mobility and Consumer Markets. “With the array of smartphones, laptops and emerging devices taking advantage of AT&T’s 3G network today, we know that customers are excited to experience higher mobile broadband speeds, and we are deploying the right technologies at the right times to help them get the most from that experience.”

The upgraded network platform could allow for theoretical peak speeds of 7.2Mbps. Typical real-world downlink and uplink speeds experienced by customers with upgraded 3G will be less than the theoretical peak and will vary based on a number of factors, including location, device, and overall traffic on the local network at a given time.

AT&T’s 3G mobile broadband network is now available in nearly 350 U.S. major metropolitan areas, with about 20 additional metro areas planned for deployment in 2009. The HSPA 7.2 technology will be deployed widely in the network, with the benefits of the network upgrade to be announced on a local basis as the faster speeds are turned up. AT&T will introduce multiple HSPA 7.2-compatible laptop cards and smartphones beginning later this year.

In 2008 and 2009 to date, high-quality 850 MHz spectrum has been deployed in more than half of AT&T’s 3G network footprint to improve overall coverage and in-building reception, with additional markets planned for later in the year.

The company is also adding fiber-optic connectivity and additional capacity to thousands of cell sites across the U.S. this year, expanding the critical connections that deliver traffic from a cell site into the global IP backbone network. These upgrades will support the higher mobile broadband speeds enabled by both HSPA 7.2 and LTE.

In addition to these projects, AT&T is deploying about 2,100 new cell sites across the U.S.